FAILURE OF THE INSTRUCTOR PILOT (CFI) TO ASSURE THAT ADEQUATE AIRSPEED WAS MAINTAINED, AFTER MANEUVERING (TURNING) FOR SPACING BEHIND ANOTHER AIRCRAFT, WHICH RESULTED IN AN INADVERTENT STALL/MUSH. FACTORS RELATED TO THE ACCIDENT WERE: THE IMPROPERLY PLANNED APPROACH AND THE CFI'S LACK OF FLIGHT EXPERIENCE IN THE MAKE AND MODEL OF AIRCRAFT.